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Agenda – May 7. Talk about review Finish Ch 22 notes Ch 23 notes Virtual lab Monday: Ch 22 and 23 bkwk due and virtual lab due. Take test if not here Wednesday. Ch. 23. Series and Parallel Circuits. Electric Circuits. Create a circuit with 1 battery and 1 light
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Agenda – May 7 • Talk about review • Finish Ch 22 notes • Ch 23 notes • Virtual lab • Monday: Ch 22 and 23 bkwk due and virtual lab due. Take test if not here Wednesday.
Ch. 23 Series and Parallel Circuits
Electric Circuits • Create a circuit with 1 battery and 1 light • Create a circuit with 2 batteries and 1 light • Create a circuit with 2 batteries and 2 lights connected in series • Create a circuit with 2 batteries and two lights in parallel • Create a circuit with 2 batteries and 1 light parallel with 2 in series
Series Circuits • A series circuit is a circuit in which all of the current travels through each device
Series Circuits • Voltage drops / potential difference • The potential difference of the generator is equal to the potential difference across each resistor (lamp)
Series Circuits • Resistance in the circuit is equal to sum of the resistances in each component
Series Circuits • Current in the circuit is equal to the potential difference in the whole circuit divided by the resistance of all of the components
Example • Three 20Ω resistors are connected in series across a 120 V generator. What is the equivalent resistance of the circuit? What is the current in the circuit?
Parallel Circuits • A circuit with several current paths
Parallel Circuits • The voltage through each path is the same • The current can be found through each individual path • The total current is that of all of the paths combined A 6Ω 24Ω 9Ω 120 V 120 V 120 V 120 V
Parallel Circuits • The resistance for the whole parallel circuit will be less than each resistor because each resistor offers an additional path for the current • Equation for finding the total resistance of a parallel circuit
Example • A 120Ω resistor, a 60Ω resistor, and a 40Ω resistor are connected in parallel and placed across a 12 V battery. • What is the equivalent resistance of the parallel circuit? • What is the current through the entire circuit? • What is the current through each branch?
23.2 Applications of Circuits
Safety Devices • Fuse – • A short piece of metal that melts when the current traveling through it is too large • Short Circuit – • When there is very low resistance in a circuit. This can easily cause fires if there is no fuse or circuit breaker to stop the high levels of current
Example • Two 60Ω resistors are connected in parallel. This parallel arrangement is connected in series with a 30Ω resistor. The combination is then placed across a 120V battery. • Draw a diagram of the circuit. • What is the equivalent resistance of the parallel portion? • What single resistance could replace the three original resistors? • What is the current in the circuit? • What is the voltage drop across the 30Ω resistor? • What is the voltage drop across the parallel portion of the circuit? • What is the current in each branch of the parallel portion of the circuit?
Bkwk • P550: 1, 4, 7, 8, 15, 21, 24, 28, 32